Modified uni-travelling-carrier photodiodes with 206 GHz bandwidth and 0.81 A W−1 external responsivity

Abstract

The accelerating demand for wireless communication necessitates wideband, energy-efficient photonic sub-terahertz sources to enable ultrafast data transfer. However, as critical components for terahertz photomixing, photodiodes face a fundamental trade-off between bandwidth and quantum efficiency, presenting a major obstacle to achieve high-speed performance with high optoelectronic conversion efficiency. Here we overcome this challenge by demonstrating an InP-based, waveguide-integrated modified uni-travelling-carrier photodiode with bandwidth exceeding 200 GHz and a bandwidth–efficiency product surpassing 130 GHz. Incorporating a spot-size converter together with optimized electric field distribution, balanced carrier transport and minimized parasitic capacitance, the device achieves a 3-dB bandwidth of 206 GHz and an external responsivity of 0.81 A W−1, setting a new bandwidth–efficiency product benchmark. Packaged with WR-5.1 waveguide output, it delivers radio-frequency power exceeding –5 dBm across the 127–185-GHz frequency range. As a proof of concept, we achieved wireless transmission over 54 m with a single-line rate of up to 120 Gbps, leveraging photonics-aided technology without requiring a low-noise amplifier. This work establishes a pathway to significantly enhance optical power budgets and reduce energy consumption, presenting a transformative step towards high-bandwidth, high-efficiency sub-terahertz communication systems and next-generation wireless networks. A uni-travelling-carrier photodiode with 206-GHz bandwidth, bandwidth–efficiency product surpassing 130 GHz and external responsivity of 0.81 A W−1 is demonstrated. Radio-frequency power exceeding –5 dBm and single-line 120-Gbps wireless transmission across 54 m were achieved, without low-noise amplifiers.